This invention relates to a printing apparatus such as a typewriter and a printer utilized as an output unit of a computer, and more particularly to a printing apparatus in which a ribbon cassette is loaded onto a carriage which is reciprocatively movable along a printing line on a printing paper.
Conventionally, there has been such a ribbon cassette as to be reversibly loaded onto the carriage. In other words, the surface of the ribbon contained in the cassette is horizontally separated into two areas and when the ribbon cassette is loaded on the carriage one side up, one of the areas on the ribbon surface is disposed along the printing line while, when it is loaded the other side up the other area is disposed along the printing line.
With the above reversible ribbon cassette, however, since there has been no means to indicate which side is now in use, if the ribbon cassette is unloaded from the carriage for some reason before the ribbon reaches to its one end, an operator very likely misloads the ribbon cassette by putting the reverse side up when resetting the cassette to the printing apparatus. This may cause a blurred printing by using the once used area of the ribbon or waste the ribbon cassette which has not yet completely been used.
Further, if the ribbon cassette to be installed is a multi-use type one, there is a possibility of the quality of printing being uneven if there is a difference in the number of times of use in places of the ribbon surface. This difference has been frequently caused by reloading the cassette with the reverse (not-on-use) side turned up by mistake after the cassette is once removed for some reason before the ribbon reaches to its one end.